:root{
  --bg:#f4f7fb; --paper:#ffffff; --ink:#182230; --muted:#5f6d7a;
  --line:#dce4ec; --accent:#0e6f74; --accent2:#174f7a; --soft:#eaf6f5;
  --warn:#fff7df; --code:#10202e; --shadow:0 8px 24px rgba(20,40,60,.08);
  color-scheme: light;
}
*{box-sizing:border-box}
html{scroll-behavior:smooth}
body{margin:0;background:var(--bg);color:var(--ink);font:17px/1.62 system-ui,-apple-system,BlinkMacSystemFont,"Segoe UI",sans-serif}
a{color:var(--accent2);text-decoration-thickness:1px;text-underline-offset:2px}
a:hover{color:var(--accent)}
.layout{display:grid;grid-template-columns:285px minmax(0,900px);gap:28px;max-width:1240px;margin:0 auto;padding:28px}
.sidebar{position:sticky;top:20px;align-self:start;background:var(--paper);border:1px solid var(--line);border-radius:14px;padding:18px;box-shadow:var(--shadow)}
.brand{font-weight:800;font-size:1.12rem;margin-bottom:4px}
.brand small{display:block;font-weight:500;color:var(--muted);font-size:.82rem;margin-top:3px}
.nav{margin-top:14px;display:grid;gap:4px}
.nav a{display:block;padding:7px 9px;border-radius:8px;text-decoration:none;color:var(--ink);font-size:.92rem}
.nav a:hover,.nav a.active{background:var(--soft);color:var(--accent);font-weight:700}
main{min-width:0}
.hero,.card,section{background:var(--paper);border:1px solid var(--line);border-radius:14px;box-shadow:var(--shadow)}
.hero{padding:28px 30px;margin-bottom:18px;background:linear-gradient(135deg,#fff 0%,#eef8f7 100%)}
.hero h1{font-size:2rem;line-height:1.15;margin:0 0 9px}
.kicker{font-size:.8rem;text-transform:uppercase;letter-spacing:.12em;color:var(--accent);font-weight:800}
.hero p{max-width:760px;margin:.45rem 0;color:#334454}
section{padding:24px 28px;margin:16px 0}
h2{font-size:1.35rem;margin:0 0 .65rem}
h3{font-size:1.08rem;margin:1.35rem 0 .4rem}
p{margin:.65rem 0}
ul,ol{padding-left:1.4rem}
li{margin:.28rem 0}
.toc{display:flex;flex-wrap:wrap;gap:8px;margin-top:16px}
.toc a{background:#fff;border:1px solid var(--line);border-radius:999px;padding:5px 10px;text-decoration:none;font-size:.84rem}
.note,.task,.warning,.definition{padding:14px 16px;border-radius:10px;margin:14px 0;border-left:4px solid var(--accent)}
.note{background:#eef7fb;border-left-color:#2d779d}
.task{background:#eef8f3;border-left-color:#348260}
.warning{background:var(--warn);border-left-color:#c49117}
.definition{background:#f5f1fb;border-left-color:#7655a6}
.label{font-weight:800;font-size:.85rem;text-transform:uppercase;letter-spacing:.05em}
code,kbd{font-family:ui-monospace,SFMono-Regular,Menlo,monospace}
code{background:#edf1f5;padding:.08em .3em;border-radius:4px}
pre{background:var(--code);color:#eef7ff;padding:15px;border-radius:10px;overflow:auto}
table{width:100%;border-collapse:collapse;margin:14px 0;font-size:.95rem}
th,td{border:1px solid var(--line);padding:8px 10px;text-align:left}
th{background:#f0f5f8}
.grid2{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:14px}
.mini-card{border:1px solid var(--line);border-radius:10px;padding:14px;background:#fbfcfd}
.bigbits{font:700 1.3rem/1.4 ui-monospace,SFMono-Regular,Menlo,monospace;letter-spacing:.08em}
.widget{border:1px dashed #a9bcc7;border-radius:12px;padding:16px;margin:14px 0;background:#fbfdfd}
.widget input,.widget select,.widget button,.widget textarea{
  font:inherit;border:1px solid #b8c7d1;border-radius:8px;padding:8px 10px;background:white;color:var(--ink)
}
.widget button{cursor:pointer;background:var(--accent);color:white;border-color:var(--accent);font-weight:700}
.widget button.secondary{background:white;color:var(--accent);border-color:var(--accent)}
.result{margin-top:10px;padding:10px 12px;border-radius:8px;background:#edf6f6;font-family:ui-monospace,SFMono-Regular,Menlo,monospace;white-space:pre-wrap}
.binary-cards{display:flex;gap:8px;flex-wrap:wrap;margin:10px 0}
.binary-card{min-width:92px;padding:12px 8px;border:2px solid #c5d0d7;border-radius:10px;text-align:center;cursor:pointer;background:#293944;color:white}
.binary-card.off{background:white;color:#87939c}
.binary-card strong{display:block;font-size:1.35rem}
.dots{display:grid;grid-template-columns:repeat(2,48px);gap:10px;width:max-content;margin:12px 0}
.dot{width:48px;height:48px;border-radius:50%;border:2px solid #71818f;background:white;cursor:pointer}
.dot.on{background:#182230;border-color:#182230}
.rgb-preview{height:100px;border-radius:10px;border:1px solid var(--line);margin-top:10px}
.footer{color:var(--muted);font-size:.82rem;padding:16px 2px 35px}
.pager{display:flex;justify-content:space-between;gap:12px;margin:18px 0}
.pager a{background:white;border:1px solid var(--line);border-radius:9px;padding:9px 12px;text-decoration:none}
.sourcebox{font-size:.86rem;color:#465767;background:#f8fafc}
details{border-top:1px solid var(--line);padding-top:8px;margin-top:10px}
summary{cursor:pointer;font-weight:700}
@media(max-width:850px){
  body{font-size:16px}.layout{display:block;padding:14px}.sidebar{position:static;margin-bottom:14px}
  .nav{grid-template-columns:repeat(2,minmax(0,1fr))}.hero{padding:22px}.hero h1{font-size:1.65rem}
  section{padding:20px}.grid2{grid-template-columns:1fr}
}
@media print{
  body{background:white}.layout{display:block;max-width:none;padding:0}.sidebar,.pager{display:none}
  .hero,section{box-shadow:none;border-color:#bbb;break-inside:avoid}
}